A Study on the Application of Oyster Powder as a Cementitious Material

• Main Authors: CHE-JUNG LEE, 李哲榮
• Other Authors: Wei-Chung Yeih
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/49863399158687090359

碩士 === 國立臺灣海洋大學 === 河海工程學系 === 93 === Abstract Oyster is the product of aquaculture feed in the southwestern coast of Taiwan and it has been reported that the oyster shells weight about 200 thousand tons per year. These oyster shells are usually disposed due to the limited remaining usages. However, such a treatment causes a serious environmental problem thus to seek a possible use of these oyster shells becomes vitally important. In this study, the oyster shell powder is used to act as a cemnetitious material such that one can use the disposal materials to create some resources. The oyster shell powders considered in this study has two types: one is simply powder made from oyster shell and the other is treated by the high temperature treatment. The powders are used to replace the cement for the Portland cement concrete and to replace the salg for the alkai-activated slag concrete.Various replacement percentages are considered as the variables to study the mechanical properties, physical properties and durability of the mortar specimens. The results show that as the replacement percentage of the oyster shell powder increases the mechanical strengths decrease, the water absorption and the shrinkage increases. Using the water/cement ratio of 0.5, the compressive strength still can reach 3000 psi (the minimum compressive strength required for the primary structure) for the replacement percenetage of oyster shell is 30%. To reach the same compressive strength for the water/cement ratio of 0.6, the replacement percentage of oyster shell powder should be lower than 20%. For all mix designs, when the replacement percentahe of oyster shell powder is 40%, the compressive strengths for them are all lower than 3000 psi thus such a concrete can be only used in the secondary structure. In addition, the results show that using the oyster shell powder with the heat treatment has a small increment in the compressive strength in comparison with the control one. Due to the high chloride contents attched on the surface of oyster shell, it is suggested an emersion of the oyster shell in the clean water for 2 days is necessary such that the chloride content can be lowered to one-tenth of the original concentration.